It looks like you have checked just about everything that needs checking. Make sure the voltages are correct at the VTEC switch and also at the PCM. You will need a diagnostic chart as well as an electronic troubleshooting manual. If all is good electrically then the next step is to check the engine oil pressure. I had a similar experience recently and after I checked the VTEC system out completely I found that the engine didn't have enough oil pressure to operate the VTEC system.

P2647 VTEC Oil Pressure Switch Circuit High Voltage - With Automatic TransmissionPossible Causes Setting Conditions
Check the engine oil level (refill as necessary to the proper level)
EOP sensor connector is damaged (check pins for damage, and for moisture)
VTEC solenoid connector is damaged (check pins for damage, and moisture)
Reset the PCM and perform the PCM “idle learn” procedure.
Update PCM to the latest software. If the problem remains, substitute a known good PCM and retest. If the problem goes away, the original PCM has failed.
Engine speed more than 1,500 rpm; ECT signal more than 167ºF, gear selector in Drive position, and the PCM detected a low voltage on the VTEC Oil Pressure switch circuit.

This code sets in 1 Trip(s).
This code will turn on the MIL (Malfunction Indicator Lamp